A hernia is the protrusion of an organ or the fascia of an organ through the wall of the cavity that normally contains it. By far the most common hernias (up to 75% of all abdominal hernias) are the so-called inguinal hernias. Inguinal hernias are further divided into the more common indirect inguinal hernia, in which the inguinal canal is entered via a congenital weakness at its entrance (the internal inguinal ring), and the direct inguinal hernia type, where the hernia contents push through a weak spot in the back wall of the inguinal canal.
Femoral hernias occur just below the inguinal ligament, when abdominal contents pass into the weak area at the posterior wall of the femoral canal. They can be hard to distinguish from the inguinal type (especially when ascending cephalad): however, they generally appear more rounded, and, in contrast to inguinal hernias, there is a strong female preponderance in femoral hernias.
Higher in the abdomen, an (internal) “diaphragmatic hernia” results when part of the stomach or intestine protrudes into the chest cavity through a defect in the diaphragm. A hiatus hernia is a particular variant of this type, in which the normal passageway through which the esophagus meets the stomach (esophageal hiatus) serves as a functional “defect”, allowing part of the stomach to (periodically) “herniate” into the chest. Hiatus hernias may be either “sliding,” in which the gastroesophageal junction itself slides through the defect into the chest, or non-sliding (also known as para-esophageal), in which case the junction remains fixed while another portion of the stomach moves up through the defect. Non-sliding or para-esophageal hernias can be dangerous as they may allow the stomach to rotate and obstruct.
An incisional hernia can develop in the scar tissue around any surgery performed in the abdominal area, from the breastbone down to the groin. Depending upon the location of the hernia, internal organs may press through the weakened abdominal wall. The rate of incisional hernia occurrence can be as high as 13% with some abdominal surgeries. These hernias may occur after large surgeries such as intestinal or vascular (heart, arteries, and veins) surgery, or after smaller surgeries such as an appendectomy or a laparoscopy, which typically requires a small incision at the navel. Incisional hernias themselves can be very small or large and complex, involving growth along the scar tissue of a large incision. They may develop months after the surgery or years after, usually because of inadequate healing or excessive pressure on an abdominal wall scar. The factors that increase the risk of incisional hernia are conditions that increase strain on the abdominal wall, such as, obesity, advanced age, malnutrition, poor metabolism (digestion and assimilation of essential nutrients), pregnancy, dialysis, excess fluid retention, and either infection or hematoma (bleeding under the skin) after a prior surgery.
Many procedures for hernia repair involve the permanent placement of surgical (prosthetic) mesh patches well beyond the edges of the weakened area or defect in the abdominal wall. The mesh is sewn or tacked to the area, bridging the hole or weakened area. As the area heals, the mesh is intended to become firmly integrated into the inner abdominal wall membrane (peritoneum) that protects the organs of the abdomen. Autogenous tissue (skin from the patient's own body) has also been used for this type of repair.
Two surgical approaches are used to treat incisional hernias: either a laparoscopic incisional herniorrhaphy, which uses small incisions and a laparoscope; or a conventional open repair procedure, which accesses the hernia through a larger abdominal incision. Open procedures may be necessary if the intestines have become trapped in the hernia (incarceration) or the trapped intestine has become twisted and its blood supply cut off (strangulation). Extremely obese patients may also require an open procedure because deeper layers of fatty tissue will have to be removed from the abdominal wall. Mesh may be used with both types of surgical access.
In both open and laparoscopic procedures, the patient lies on the operating table, either flat on the back or on the side, depending on the location of the hernia. General anesthesia is usually given, though some patients may have local or regional anesthesia, depending on the location of the hernia and complexity of the repair. A catheter may be inserted into the bladder to remove urine and decompress the bladder. If the hernia is near the stomach, a gastric (nose or mouth to stomach) tube may be inserted to decompress the stomach.
In an open procedure, an incision is made just large enough to remove fat and scar tissue from the abdominal wall near the hernia. The outside edges of the weakened hernial area are defined and excess tissue removed from within the area. Mesh is then applied so that it overlaps the weakened area by several inches (centimeters) in all directions. Non-absorbable sutures are placed into the full thickness of the abdominal wall. The sutures are tied down and knotted.
In the less-invasive laparoscopic procedure, multiple small incisions will be made to access the hernia site—the laparoscope is inserted in one incision and surgical instruments in the others to remove tissue and place the mesh in the same fashion as in an open procedure. Significantly less abdominal wall tissue is removed in laparoscopic repair. The surgeon views the entire procedure on a video monitor to guide the placement and attachment of the mesh.
Patients will usually go home the day of surgery and can expect a one- to two-week recovery period at home, and then a return to normal activities. Although good outcomes are expected with incisional hernia repair, particularly with the laparoscopic method, recurrence rates after the first repair of an incisional hernia can range from 25-52%.